Lighthouse sign is seen in ASOM in which stage
**Core Concept**
The Lighthouse sign, also known as the "lighthouse appearance," is a clinical finding observed in acute suppurative otitis media (ASOM). It is a characteristic sign that helps in diagnosing the stage of ASOM.
**Why the Correct Answer is Right**
The Lighthouse sign is seen when the tympanic membrane is perforated, and the fluid in the middle ear cavity is under pressure. This causes the tympanic membrane to bulge outward, resembling the beam of a lighthouse. The sign is indicative of the acute stage of ASOM, where the infection has caused significant inflammation and fluid accumulation in the middle ear. The fluid pressure pushes the tympanic membrane outward, leading to the characteristic lighthouse appearance.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the Lighthouse sign is not typically seen in the initial or prodromal stage of ASOM, where the infection is just beginning.
* **Option B:** This option is incorrect because the Lighthouse sign is not a characteristic finding in chronic suppurative otitis media (CSOM), where the infection is long-standing and the middle ear is often dry.
* **Option C:** This option is incorrect because the Lighthouse sign is not seen in cases of otitis externa, where the infection affects the outer ear canal rather than the middle ear.
**Clinical Pearl / High-Yield Fact**
The Lighthouse sign is a valuable clinical indicator of acute ASOM, and its presence should prompt further investigation and treatment to prevent complications.
**Correct Answer:** D.